A reactor is one of the components of a circuit that performs a voltage step up or step down operation. For example, Patent Literature 1 discloses a reactor that is used for a converter mounted on a vehicle such as a hybrid vehicle. The reactor includes a combined product being a combination of a coil member having a pair of coils coupled to each other in a paralleled state and an annular magnetic core fitted into the coils so as to penetrate through the coils. Further, there is another type of reactor in which the combined product is stored in the case and then sealed with resin.
In connection with the reactor including such a case, generally the case is made of metal because it is necessary to dissipate the heat generated at the coil member in operation. For example, as the case, an aluminum die-cast product is used. With the reactor including such a metal-made case, the coil member of the combined product and the bottom face of the case need to be electrically insulated from each other. Accordingly, conventionally, the combined product is fixed to the bottom face of the case by, for example, applying an adhesive agent being an insulating resin to the bottom face of the case, to secure electrical insulation between the bottom face of the case and the coil member of the combined product by an insulating layer, which is formed by the adhesive agent being cured.